Rostromedial tegmental nucleus-substantia nigra pars compacta circuit mediates aversive and despair behavior in mice

AbstractAppetitive locomotion is essential for animals to approach rewards, such as food and prey. The neuronal circuitry controlling appetitive locomotion is unclear. In a goal-directed behavior—predatory hunting, we show an excitatory brain circuit from the superior colliculus (SC) to the substantia nigra pars compacta (SNc) to enhance appetitive locomotion in mice. This tectonigral pathway transmits locomotion-speed signals to dopamine neurons and triggers dopamine release in the dorsal striatum. Synaptic inactivation of this pathway impairs appetitive locomotion but not defensive locomotion. Conversely, activation of this pathway increases the speed and frequency of approach during predatory hunting, an effect that depends on the activities of SNc dopamine neurons. Together, these data reveal that the SC regulates locomotion-speed signals to SNc dopamine neurons to enhance appetitive locomotion in mice.

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Struktur und Efferenzen der Substantia nigra pars compacta beim idiopathischen Parkinson-Syndrom

Fortschritte der Neurologie · Psychiatrie ◽

10.1055/a-1149-9280 ◽

2020 ◽

Vol 88 (09) ◽

pp. 591-599

Author(s):

Peter Urban ◽

Bjorn Falkenburger ◽

Wolfgang H. Jost ◽

Gerhard Ransmayr ◽

Peter Riederer ◽

...

Keyword(s):

Substantia Nigra ◽

Substantia Nigra Pars Compacta

ZusammenfassungEs besteht Konsens, dass das neuropathologische Merkmal des idiopathischen Parkinson-Syndroms (IPS) der neuronale Zellverlust der Substantia nigra pars compacta (SNc) in Verbindung mit einer Lewy-Pathologie ist. Die transsynaptische Ausbreitung der Lewy-Pathologie wird als wesentlich in der Parkinson-Pathogenese angesehen. Daher ist die Kenntnis präexistenter neuroanatomischer Verbindungen der SNc wesentlich. Wir beschreiben hier neuere tierexperimentelle Befunde zu den afferenten und efferenten Projektionen der SNc und diskutieren die Evidenz für und gegen die sequentielle transsynaptische Ausbreitung der Lewy-Pathologie in der Pathogenese des IPS.

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Substantia nigra neuromelanin magnetic resonance imaging in patients with different subtypes of Parkinson disease

Journal of Neural Transmission ◽

10.1007/s00702-020-02295-8 ◽

2021 ◽

Author(s):

Lu Wang ◽

Yayun Yan ◽

Liyao Zhang ◽

Yan Liu ◽

Ruirui Luo ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Substantia Nigra ◽

Parkinson Disease ◽

Clinical Symptoms ◽

Dopamine Neurons ◽

Substantia Nigra Pars Compacta ◽

Resonance Imaging ◽

Mean Values

AbstractNeuromelanin (NM) is a dark pigment that mainly exists in neurons of the substantia nigra pars compacta (SNc). In Parkinson disease (PD) patients, NM concentration decreases gradually with degeneration and necrosis of dopamine neurons, suggesting potential use as a PD biomarker. We aimed to evaluate associations between NM concentration in in vivo SN and PD progression and different motor subtypes using NM magnetic resonance imaging (NM-MRI). Fifty-four patients with idiopathic PD were enrolled. Patients were divided into groups by subtypes with different clinical symptoms: tremor dominant (TD) group and postural instability and gait difficulty (PIGD) group. Fifteen healthy age-matched volunteers were enrolled as controls. All subjects underwent clinical assessment and NM-MRI examination. PD patients showed significantly decreased contrast-to-noise ratio (CNR) values in medial and lateral SN (P < 0.05) compared to controls. CNR values in lateral SN region decreased linearly with PD progression (P = 0.001). PIGD patients showed significant decreases in CNR mean values in lateral SN compared to TD patients (P = 0.004). Diagnostic accuracy of using lateral substantia nigra (SN) in TD and PIGD groups was 79% (sensitivity 76.5%, specificity 78.6%). NM concentration in PD patients decreases gradually during disease progression and differs significantly between PD subtypes. NM may be a reliable biomarker for PD severity and subtype identification.

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